The present invention relates to a piston compressor in which pistons reciprocate in the axial direction of a drive shaft and also to a process for producing the compressor.
Generally, a piston compressor has a cylinder block containing cylinder bores and a pair of housing members arranged on each side of the cylinder block. Each cylinder bore houses a piston for compressing a refrigerant. A suction chamber and a discharge chamber through which the refrigerant passes are defined in one of the housing members. A crank chamber in which a crank mechanism is located is defined in the other housing member. The crank mechanism reciprocates pistons based on rotation of the drive shaft.
Interfaces between the cylinder block and each housing member are exposed to the air. The interfaces increase the likelihood that fluid such as the refrigerant in the housing members will leak.
There is a proposed for reducing fluid leakage; that is, to reduce the number of interfaces, or junctions. For example, Japanese Unexamined Patent Publication No. Hei 10-306773 discloses an apparatus where a cylinder block 101 is located in a space defined by a front housing member 102 and a rear housing member 103, as shown in FIG. 4. According to this apparatus, there is only one junction 104 exposed to the air between the housing member 102 and 103, and thus leakage of the fluid in the space defined between them can be reduced.
However, the cylinder block 101 is located in the space, after the housing members 102 and 103 are combined with each other. When the housing members 102 and 103 are combined with each other in a compressor assembly, the cylinder block 101, the crank mechanism, the pistons, drive shafts and other elements that move relative to one another need be arranged so that they can operate. This makes the assembly extremely difficult and reduces productivity by a wide margin.
The above publication also discloses another apparatus, in addition to that shown in FIG. 4, in which the cylinder block is housed in the crank chamber. However, since the junction between the housing members is adjacent to the suction chamber and the discharge chamber, chambers cannot be sealed fully.
It is an object of the present invention to provide a piston compressor which can achieve secured sealing between housing members and which can improve productivity.
In order to attain the above objective, the present invention provides the following piston compressor. The piston compressor comprises a front housing member and a rear housing member connected to the front housing member. A suction chamber and a discharge chamber are defined either in the front housing member or in the rear housing member. A cylinder block is accommodated in a space defined by the front housing member and the rear housing member and isolated from ambient air. The cylinder block is fixed to one of the housing members. Cylinder bores are defined in the cylinder block. Pistons are accommodated in the cylinder bores to reciprocate therein, respectively. A drive shaft drives the piston. The drive shaft is supported by the cylinder block. Fluid is compressed and discharged due to reciprocation of the piston.
The present invention also provides a process for producing a piston compressor. The process for producing a piston compressor. The process comprises connecting a drive shaft to a piston, supporting the piston by a cylinder block, accommodating the piston in a cylinder bore which is formed in the cylinder block, preparing a front housing member and a rear housing member. A suction chamber and a discharge chamber are formed either in the front housing member and the rear housing member. The process has connecting the front housing member to the rear housing member when the cylinder block is fixed to one of the front housing member and the rear housing member. The cylinder block is accommodated in a space defined by the front housing member and the rear housing member and is isolated from ambient air.
Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.